In medical care facilities, infusion of medical fluids into a patient is a commonly performed patient care operation. A fluid infusion device, such as an infusion pump, is typically configured to infuse a fluid from a fluid source into a patient through a vascular access device (VAD) such as a syringe or a catheter. If an occlusion occurs between the pump and the VAD, fluid does not reach the vascular system as intended and blood may back up resulting in clotting and attendant risks.
Prior to starting a fluid delivery session, a caregiver typically sets up the infusion device to alert the caregiver when fluid pressure in a infusion line exceeds a pressure threshold so that the caregiver could take corrective action to avoid possible harm to the patient. Current methods of setting up infusion devices include the caregiver entering a ‘care area profile’, e.g. NICU, for which the pressure limits and associated rules have been pre-configured. In some pumps, these pre-configured values may be adjusted by the caregiver while in other pumps the pre-configured values are fixed and all have limited ranges. Certain pumps are pre-configured to acquire a value during power-on, which the caregiver may or may not be allowed to control to adjust, though this acquired value is over a defined range of pressure values.
Caregivers may adjust pressure limits for several reason. For example, caregivers adjust pressure limits to minimize time to detection of an occlusion. This is important to avoid undue interruption of delivery of medication, to avoid exposure of the patient's vessels and tissue to a higher pressure than necessary and to avoid false alarms which would be issued due to occlusion, causing an interruption of medication delivery.
While mathematical formulae for calculating a pressure threshold are known in the art, caregivers typically select the pressure threshold for alarm based on their experience or using “rule of thumb” calculations. Often, caregivers do not have access to parameters such as catheter and tubing resistance, fluid viscosity and so forth, so caregivers often use preset values, perhaps based on the location of care or a flow rate. If the pressure threshold is set too low, then the fluid delivery equipment may frequently and unnecessarily alert the caregiver. Such false alarms take the caregiver's valuable time away from other medical tasks, interrupt flow of medication and elevate risk of clot formation in the VAD. On the other hand, if the pressure threshold is too high, then increased fluid pressure may go unnoticed, thereby potentially harming the patient. Furthermore, a method sometimes used by caregivers is to set the pressure threshold simply to be a certain amount over the current pressure. This method may set the pressure threshold incorrectly high or low if the current pressure was erroneous, e.g., because there was an existing elevated pressure in the fluid line.
A more exact method for setting fluid pressure thresholds for alerting a healthcare professional when infusing a medical fluid into a patient is needed.